June 3, 2012: In a much-anticipated speech, embattled Syrian president Bashar al-Assad blames foreign powers and "terrorists" for the violence that has wracked the country for the last 15 months. (AP)
(AP2012)

A Senate panel is pushing to strip funding for helicopter contracts with a Russian firm supplying the Syrian regime, after the Pentagon tried to defy congressional warnings and move ahead with the chopper deal.

The Senate Defense Appropriations subcommittee on Tuesday signed off on a 2014 defense spending bill that guts funding for the Mi-17 helicopters and includes restrictions on purchases from the Russian company that makes them -- Rosoboronexport.

The move is the latest play in a long-running dispute between the Pentagon and Congress. The Pentagon last month announced a new contract with the company, to produce military helicopters that will go to Afghan security forces. The Pentagon argues the helicopters are the only option, but Sen. John Cornyn, R-Texas -- who has led the charge against them -- is adamant that the U.S. find an alternative considering the company's ties to the government of Syrian President Bashar Assad.

The decision by the leaders of the defense subcommittee to strip the funding was hailed by Cornyn.

"The Obama administration's arrogant circumvention of Congress' efforts to put an end to our role in subsidizing Assad's murderous campaign against his own people is mystifying and disturbing, particularly when there are other ways to provide helicopters for the Afghans," he said in a statement. "American taxpayers should not be indirectly subsidizing the murder of Syrian civilians, and I'm pleased committee leaders have joined this effort to end our relationship with Assad's arms supplier."

Cornyn first challenged the Pentagon over a prior contract with Rosoboronexport last year, and was able to successfully pass an amendment in November barring the use of funds for contracts with the company.

But the latest contract used money from the fiscal 2012 budget, which was approved before Cornyn's amendment.

The most recent $572 million contract would purchase 30 Mi-17 helicopters for Afghan security forces, which deals with counterterrorism and other missions. The contract also includes spare parts, test equipment and engineering support services. The contract lasts through the end of 2014. It's unclear whether Congress can do anything about that particular helicopter purchase, or just block future purchases.

The Pentagon has defended its arrangements with Rosoboronexport, arguing that the Mi-17 helicopters are "uniquely suited" for Afghanistan.

Spokeswoman Maureen Schumann said last month that the Russian government has notified the U.S. that Rosoboronexport is the "sole legal exporter of Mi-17s for military use."

"The department explored whether there were any alternatives to contracting with Rosoboronexport to meet this requirement, but none were identified," she told FoxNews.com.

As for the company's work with Syria, Russia's government has claimed the company's arms cannot be used against Syria's civilian population.

But Human Rights Watch claimed last year that Rosoboronexport nevertheless appears to be Syria's main weapons supplier, questioning how the company tracks how its weapons are being used.

The Pentagon contract comes at a vital time, as the Obama administration steps up its support for the anti-Assad opposition by pledging to provide small arms to certain opposition groups. The contract potentially puts the U.S. government in the uncomfortable position of funding a company that is aiding the other side of that civil war.

Despite Russia's claims, a Pentagon official wrote a letter to Cornyn in March 2012 that acknowledged "evidence" that Rosoboronexport's arms "are being used by Syrian forces against Syria's civilian population."